Conveyor line loader for multi-tiered rolling carts

ABSTRACT

A cart loader assembles objects advancing along an infeed conveyor line into arrayed rows of parallel columns, and transfers these arrayed rows of columns to individual shelves of a multi-tiered rolling cart. The cart loader has an external frame enclosing a vertically elongated front elevator and a central staging zone fed by the infeed conveyor. A multi-deck elevator has decks spaced apart vertically by a distance corresponding to the vertical distance between shelves on the multi-tiered cart, latched to the frame for loading. A plurality of horizontally deployable and retractable pushers are each aligned respectively with one shelf, and positioned for delivery of objects from the elevator zone to the cart. A preferred deck-loading and cart-shelf loading sequence achieves minimum loading cycle time coupled with maximum time within each cycle for replacing each loaded cart with an empty cart for the next loading operation.

TECHNICAL FIELD

This invention relates to cart loaders for use in food packaging andother production lines for loading conveyor-delivered articles onto theshelves of multi-tiered rolling carts. In particular, the cart loadersof this invention are useful in dairies and food production plants,where food containers such as half-gallon or one-gallon milk bottles orcartons are filled, sealed, and delivered along a production line.Rolling carts have often proved more effective than conventional casesfor transporting the product from the packaging plant to the point ofsale, and automated cart loaders are urgently needed to minimize thehuman labor required to load containers onto the shelves of rollingcarts.

BACKGROUND ART

A number of patents have proposed various devices for loadingmulti-tiered carts, but the task of arranging a plurality of articlesadvancing in a column along a production line by assembling them intocompact rows and columns arrayed on the multiple shelves of a rollingcart requires successive staging of two or four or six columns ofarticles aligned in rows, in order to provide compact loading of eachshelf of the multi-tiered cart, and raising or lowering of the cart orthe articles is also required in order to align them for loading ontoeach shelf in turn.

Kampfer U.S. Pat. No. 3,637,095, issued in 1972, shows in FIG. 1 amachine with vertically movable shelves, all collected at the bottom oftheir stroke at 75 in FIG. 1 of the patent. These shelves aresuccessively loaded at the level of the input conveyor 14 in the patentand then successively raised to positions 71, 72, 73 and 74.

Schroeder U.S. Pat. No. 1,518,278 loads successive pallet trays ofbricks, stacked one above the other, on an elevator for transfer to aspecialized truck with a series of pallet engaging flanges 110, whichunloads the entire elevator in a single step and delivers all of thepallets to a kiln for curing. Carothers U.S. Pat. No. 2,935,908 shows asimilar arrayed plurality of forks successively picking up green ceramictiles from their delivery conveyor and arraying them vertically forglazing and curing.

Several Lindberg hospital tray loading patents show a rolling cart,where successive food trays delivered by a conveyor are arrayed in avertically reciprocated elevator rack 7. In Lindberg's earliest U.S.Pat. No. 4,032,027, issued in 1977, the arrayed trays are transferred bya pusher 8 or 9 from the elevator to the rolling cart tiers. The laterLindberg U.S. Pat. Nos. 4,203,696 and 4,277,216 show horizontallymovable belt drive arms which reach into the cart and remove trays forredelivery to a conveyor leading to the dishwasher, and in the 1981 '216patent such arms can be used either for loading or unloading the cart.

Grasvoll U.S. Pat. No. 3,594,977, issued in 1971, shows a rolling cartloader for milk cartons which raises the cart 27 successively from onelevel to another, while rows of milk cartons are assembled on a conveyorplate 8 and then delivered by a pusher 9 and stripper plate 18 tosuccessive shelves of the rolling cart as the cart 27 is movedvertically from level to level by elevator 24. At column 4, lines 61-66,the reversal of this mechanism is suggested, with the cart being fixedand the conveyor plate 8, pusher 9 and stripper plate 18 being movedvertically, but such a reversed mechanism is not illustrated orotherwise disclosed in this Grasvoll patent.

Other patents show many different kinds of vertical conveyor stages,including one for loading tires on a rolling cart, Leblond Uniroyal U.S.Pat. No. 3,696,949, and Temple U.S. Pat. No. 3,584,750 shows racks ofbread loaves assembled on an elevator 38 from a delivery conveyor 263and then all moved together by a pusher 304 onto a multi-tiered rollingcart. Ashford U.S. Pat. No. 2,661,100 shows a bottle-rolling case loaderfor a rolling cart hoisted on an elevator.

The operations of assembling or "staging" the advancing procession ofcontainers into groups for shelf loading requires momentaryinterruptions in the procession each time an assembled column is movedsidewise to make room for the succeeding column, and each time thestaged rows of columns are moved onto the cart shelves. If these periodsof interruption of the advancing procession of containers are minimized,the loading operation is thereby made more efficient.

A further interruption in the normal loading operation often occurs whenthe cart has been completely filled and must be disengaged from theloading station and rolled away, to permit an empty cart to be rolledinto position for loading.

In the Kampfer U.S. Pat. No. 3,637,095 discussed above, fiveindividually elevated shelves are successively filled with containersand raised into positions aligned horizontally with the shelves of anadjacent rolling cart. These elevated shelves are then moved en masse toproject into the cart, between the cart shelves, by advancing an entireinternal subframe of the overall device, and retainer bars are then heldstationary behind the containers as the elevated shelves are withdrawntogether, leaving the entire cart fully loaded with containers. Ifdesired, as shown in this patent, the adjacent one-half of each cartshelf may be loaded simultaneously from one side of the cart, and thecart may then be reversed for loading the empty remaining halves of eachcart shelf simultaneously by a similar operation. While this Kampfercart loader thus occupies most of its cycle time in successively loadingand raising individual elevated shelves, the complex mechanism requiredto perform this function and then to move the entire subframe back andforth for each cart loading step requires close tolerances infabrication and alignment, with many moving parts that may mis-align orjam in operation, and considerable loads must be moved both verticallyand horizontally by the drive mechanism.

Kampfer's cart loader is understood to have been manufactured byEx-Cell-O Materials Handling Co., an affiliate or successor to ConveyorSpecialties Co., the assignee of the Kampfer's patent. The same companymanufactures a travelling tray cart loader in which trays move in arectangular path: they are loaded, moved upward, advanced forward acrossthe top of the machine, lowered downward into alignment with the cartshelves, unloaded onto the cart shelves and lowered further for returnto the tray loading station, sweeping out a rearward, upward, forward,and downward rectangular path during a full cycle of machine operation.This travelling tray cart loader thus requires a great number of traysand substantial power requirements as well as complex mechanism and theneed for a depressed pit below normal floor level or an elevated ramp toraise the empty carts, to permit the return of unloaded trays to thetray loading station.

The cart loaders of the present invention provide many advantages overthese conventional prior art cart loader proposals.

BRIEF SUMMARY OF THE INVENTION

The cart loaders of this invention employ a simple multi-deckcounterbalanced elevator, indexed into successive positions with eachdeck in turn aligned with an in-feed conveyor and a staging platformfrom which advancing containers are loaded directly onto the elevatordecks. Preferably, the loaded elevator is unloaded directly onto theshelves of an adjacently latched rolling cart from its two limitpositions, its lowermost position and its uppermost position, followingwhich the loaded cart is unlatched and withdrawn, to be replaced by anempty cart for the next cart loading cycle. The central elevator deck ispreferably fixed relative to the elevator frame, while the otherelevator decks are adjustable for alignment with different rolling cartshelf levels. Fine adjustments of the elevator loading height are madeby a turnbuckle type connection joining a counterweighted balance arm tothe elevator by a chain and sprocket connection. The exact length of theelevator stroke may be adjusted by a radial screw adjustment on thepivoted balance arm. Supporting the arm from the main frame is a seriesarray of pneumatic cylinders whose piston rods may be extended orcontracted independently to provide different successive elevatorpositions. In order to raise a vertical sliding gate mounted on the sideof each rolling cart from its gate position maintaining containers onthe cart shelves to its loading position in which access to the shelvesis cleared for sliding sidewise container loading, a gate lift mechanismis mounted on the upper front portion of the frame above cart latchblocks securing the cart in position during the loading operation andreleasing it when loading is completed.

Pneumatically actuated pushers are provided to propel staged arrays ofcontainers from the in-feed conveyor onto the elevator decks, and fromthe elevator decks onto the rolling cart shelves. As the cycleprogresses, fail safe sensors are preferably provided to monitor eachsuccessive step in the loading operation as rows of columns areassembled in the staging zone. Electrical or pneumatic limit switchesare employed to assure the completion of each step in turn before thenext step is automatically actuated. An electric motor is preferablyemployed to power the in-feed conveyor, and pneumatic cylinderspreferably raise and lower the elevator and advance the pushers asrequired. The switching and cycle control of each successive operatingstep in the cycle may be electrical, but in production plants whereconveyor lines are exposed to liquids, pneumatic control systems areoften preferred.

The cart loaders of this invention are compact and economical inconstruction and highly efficient in operation with a minimum number ofmoving parts vulnerable to misalignment or jamming. At the same time, byperforming the transfer operation by loading assembled and stagedcontainers onto the adjacent cart shelves in two successive operations,a period of time amounting to more than one-half of the overalloperating cycle is available for the disengagement and removal of eachloaded cart and the positioning and engagement of the next unloadedcart, ready for the next loading operation, minimizing interruptions inconveyor line operation and achieving maximum efficiency in cartloading.

Accordingly, a principal object of the invention is to provide sturdy,durable, compact and economical automatic cart loaders capable ofassembling containers advancing along an infeed conveyor into arrayedcolumns and loading them successively onto the shelves of a multi-tieredrolling cart, making highly efficient use of the cargo carrying capacityof a counterbalanced elevator, and providing maximum periods out of eachoperating cycle during which carts may be changed.

Another object of the invention is to provide such cart loadersoccupying minimum floor space and requiring minimum installation effortswhen being set up, leveled and placed in operation.

A further object is to provide such cart loaders which are easilyadjusted to cooperate with multi-tiered rolling carts having differinginter-shelf spacing or varying shelf heights above the floor.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the features of construction,combinations of elements, and arrangement of parts which will beexemplified in the constructions hereinafter set forth, and the scope ofthe invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

THE DRAWINGS

FIG. 1 a front corner is a perspective view of a cart loader embodyingthe features and advantages of the present invention, with the rollingcart removed to show the elevator in its upper position with its topdeck loaded with plastic one-gallon milk containers;

FIG. 2 is a right side elevation view of the same cart loader showingthe rolling cart in adjacent latched engagement with the device, andwith all five shelves of the rolling cart ready to be loaded with milkcontainers;

FIG. 2A is a top plan view of the cart loader of FIG. 2;

FIG. 3 is a left rear corner perspective view of the same cart loadershowing the counterweight in its lowermost position corresponding to theuppermost position of the elevator;

FIG. 4 is a fragmentary greatly enlarged right rear corner perspectiveview showing the elevator's counterweight chain and its rear sprocket;

FIG. 5 is an enlarged fragmentary left rear corner perspective viewshowing the counterweight and the adjustable connections with itspneumatic cylinder and its elevator chain as well as its pivotalconnection to the frame;

FIG. 6 is a fragmentary enlarged left side elevation view of the samecounterweight and adjustable connections;

FIG. 7 is a fragmentary enlarged right side elevation view of the rearportion of the cart loader showing the counterweighted balance arm, itspivotal support, its series connected dual pneumatic cylinder drivedevice, and its elevator chain, with adjustable connections to thebalance arm;

FIG. 8 is a right front corner view of the cart loader with the rollingcart engaged in loading position;

FIG. 9 is a greatly enlarged left side perspective view of the upperportion of the elevator showing the upper deck level adjustment and thelateral guide bars;

FIG. 10 is a greatly enlarged right front corner perspective view of theupper cart latch mounted on the corner post of the main frame;

FIG. 11 is a greatly enlarged left front corner perspective view of thelower left cart latch;

FIG. 12 is left front corner perspective view of the lower right frontcorner of the cart loader showing the lower right cart latch;

FIG. 13 is a fragmentary left side view of the central portion of thecart loader showing the in-feed conveyor, the assembly platform, and thethree elevator decks with the uppermost deck being in position ready forloading; and

FIGS. 14A through 14H are schematic diagrams showing successive steps inan operating cycle.

DETAILED DESCRIPTION OF THE BEST MODE FOR CARRYING OUT THE INVENTION

The rolling cart loaders 20 of the present invention are unusuallycompact, fast, and reliable devices, customarily fabricated of stainlesssteel and enclosed inside protective screening to avoid accidentalinjury to personnel. The protective screening has been removed in thedrawings for clarity of disclosure.

The output end of the loader 20 shown in FIG. 1 is normally consideredthe front, and for convenience the left side and right side, as shown inFIG. 1, are at the left and right sides of the viewer, standing in frontof the machine. As shown on the right side view of FIG. 2, the mainframe 21 is preferably formed of rectangular tubular box beams weldedtogether to form a sturdy box with front and rear corner posts 22, frontand rear bottom rails 23, front and rear top rails 24, right and leftlower side rails 26, and right and left upper side rails 27, withintermediate side posts 28, 29 and 31 positioned vertically and spacedat intervals from the front corner toward the rear corner of each sideof the frame. Heavy duty box beams formed of double square cross-sectionbeams welded spanning the transverse width of the machine are employedat two locations to carry concentrated loads. These are the centraltransverse beam 32 (FIG. 7) extending horizontally across the frame,with its ends welded to the central side posts 29 and the central toptransverse box beam 33 formed of two square cross-sectioned box beamsspanning the space between the two upper side rails 27 toward the rearof the main frame 21. Both of these transverse dual box beams are shownin FIG. 7 where their connections to the heavy pivoted counterweightbalance arm are clearly illustrated.

As indicated in FIG. 2, the cart loaders 20 of the present invention maybe divided into four vertical zones: a rear counterweight zone 34, acentral staging zone 36, an elevator zone 37, and a cart loading zone 38directly in front of loader 20. As indicated in FIG. 2, thecounterweight zone extends from the central vertical side posts 29 tothe rear corner posts 22. The staging zone extends from the forward sideposts 28 to the central side posts 29. The elevator zone extends fromthe corner 22 to the forward side posts 28, and the cart loading zonecomprises the volume of space directly in front of the cart loader 20,where carts are engaged, loaded, disengaged, and removed.

While other rolled sections of such material as stainless steel, forexample angles or channels, may be used to form these various componentparts of the main frame 21, the use of tubular box beams preferablysquare in cross-section is preferred for light weight, sturdy stiffnessand ease of cleaning. Adjustable supporting feet 30 are mounted at thelower ends of the corner posts 22 and of the forward side post 28 topermit leveling of the frame 21, avoiding distortion and equalizingfloor loads while supporting the loaded elevator zone in a firm, stableorientation on the plant floor.

No pits or excavations of any kind are required to accommodate the cartloaders of this invention. Rolling cart 39, shown in the cart loadingzone 38, is simply rolled up to the front face of the cart loader 20, asindicated in FIG. 2, and latched in position as described below. In theillustrated embodiment of the invention the multi-tiered cart 39 isprovided with five shelves, and the elevator 41 reciprocating in theelevator zone 37 is provided with three decks spaced apart to match theintershelf spacing of cart 39. In the preferred embodiments of theinvention the cart is provided with an odd number of shelves 2N+1 whilethe elevator is provided with an odd number of N+1 decks, facilitatingthe loading operation in a highly efficient sequence, as hereinafterdescribed.

Many rolling carts 39 are provided with a sliding side gate 122 whichmay be raised and lowered, like the side gate of a hospital bed, from alower gate position in which its horizontal side rails are positionedseveral inches above the cart shelves to retain containers loadedthereon, to an upper position where the gate side rails are positionedjust below the level of the next overlying cart shelf, thereby exposingthe space beside the cart shelves for unobstructed container loading.For actuation of this cart gate, a gate lift 42 actuated by a pneumaticcylinder is mounted vertically in the center of the front top rail 24,as shown in FIG. 1.

Elevator 41 is shown in the right central portion of FIG. 1 and in thecenter of FIG. 2, and the elevator may also be seen in FIGS. 8 and 9 aswell as FIG. 13. Essentially elevator 41 is a box frame supporting threeelevator decks, a central deck 43 and upper and lower decks 44 and 46,whose spacing from the central deck 43 is adjustable withinpredetermined limits. As indicated in FIG. 9, slotted angle brackets 47bolted to the corner posts 48 of the elevator 41 underlie upper deck 44as well as lower deck 46 (FIG. 13) and a jack screw 49 positioned in athreaded aperture in a block bolted to each corner post 48 below eachangle bracket 47 is adjusted to achieve the desired interdeck spacing,after which the bolts anchoring brackets 47 to corner posts 48 aretightened to secure the adjustable decks 44 and 46 in theirpredetermined, adjusted positions. A guide bar 50 extends across eachend of each deck of elevator 41 to keep objects from sliding off thedeck.

As shown in FIG. 2 and FIG. 13, a series of horizontally slidablelaterally elongated pushers is arrayed one above the other facing eachindexed deck position of the elevator along the front portion of thestaging zone facing the elevator zone. These pushers comprise a centralpusher 51, two upper pushers 52 and 53, and two lower pushers 54 and 56.Each of these pushers is a block-shaped plate extending across the widthof the elevator deck and having a height corresponding to roughlyone-half the height of the containers to be delivered to the elevatordeck. Each pusher is provided with a horizontal pneumatic actuatingcylinder extending rearward, with the central pusher 51 having an extralong cylinder 57 providing three stop positions. As shown in FIGS. 2 and13, the two upper pushers 52 and 53 are actuated by upper cylinders 58and 59, and the two lower pushers 54 and 56 are actuated by lowercylinders 61 and 62. Preferably the two upper cylinders 58 and 59 areactuated simultaneously, to provide synchronized forward pushing ofcontainers standing on their elevator decks directly onto the adjacentcart shelves. The same is true of lower cylinders 61 and 62, which arenormally actuated simultaneously to cause lower pushers 54 and 56 toadvance to dash line positions 54C and 56C shown in FIG. 13, therebydelivering the containers arrayed before them on the two lower elevatordecks 43 and 46 directly to the two lower cart shelves of cart 39.

The three stop positions of central pusher 51 actuated by the extra longcentral pusher cylinder 57 will be discussed in more detail below, sincethese three stop positions of this central pusher 51 are employed insuccessive staging steps assembling rows of columns of containers in thestaging zone, and then delivering these assembled rows of columns toeach elevator deck in turn as the elevator is indexed through itsvarious successive positions, as shown in FIGS. 14A through 14H.

The Staging Zone

Staging zone 36 first receives the advancing containers delivered by theinfeed conveyor line 63, best shown in FIG. 13. There container 64 isillustrated arriving on the conveyor 63, which is shown endwise incross-section, delivering container 64 away from the viewer toward thecart loader 20. The return portion 66 of conveyor 63 is shown belowcontainer 64, thus forming an endless belt of conveyor segments driven,for example, by a conventional conveyor chain whose drive sprocket 67 ismounted on the drive shaft of an infeed conveyor motor 68 mounted on theleft side of main frame 21, as best seen in FIG. 2A. The infeed conveyor63 may receive containers delivered by an abutting conveyor line, or itmay be elongated to extend across the plant to a previous packaging orlabelling station, if desired.

Directly beside infeed conveyor 63 extending along the front edgethereof is a retractable guide curb 69, shown in FIG. 13. This is anelongated block actuated by a vertically positioned pneumatic cylinderwith a short stroke connected to reciprocate the guide curb verticallybetween a lower retracted position, shown in solid lines in FIG. 13, toa deployed upper position shown in dash lines where it stands upwardbeside the lower edge of containers 64 as they advance along and feedconveyor 63. Drive curb 69 serves to retain containers 64 in substantialalignment as they progress across the infeed conveyor, assuring thatcontainers 64 will not catch, snag, or twist during their lateralprogress across frame 21.

Appropriate sensors indicate when a full column of containers 64 hasadvanced to fill infeed conveyor 63 across the entire width of frame 21.Central pusher 51 is then actuated to advance one container width, todeliver this column of containers 64 forward to the infeed stagingplatform 71 directly beside infeed conveyor 63.

During this delivery stroke the retractable guide curb 69 isautomatically lowered by its pneumatic cylinder to permit the forwardmovement of the entire column of containers 64 onto the staging platform71. At the same time, an infeed gate 72 with its own actuating cylinder73 is deployed in a forward direction across the infeed conveyor 63 toblock the advance of additional containers until this staging stroke hasbeen completed.

As the central pusher 51 retracts back across infeed conveyor 63, itengages and draws back infeed gate 72, releasing the next container tobe delivered by infeed conveyor 63. Guide curb 69 is again deployedupward as well. When the second column of infeed containers hasprogressed across the width of infeed conveyor 63 to a position alignedwith the containers standing on staging platform 71, guide curb 69 isretracted and pusher 51 is again actuated, if elevator 41 is inposition. While guide curb 69 is retracted and infeed gate 72 isdeployed, this stroke of pusher 51 delivers the front column ofcontainers 64 sliding from staging platform 71 onto the adjacent deck ofelevator 41, i.e., from the staging zone, as shown in FIG. 14A to theelevator zone as shown in FIG. 14B. In FIG. 13 this is the upper deck 44of elevator 41. The center deck 43, and lower deck 46 are shown as fullyloaded with four columns each of containers 64 in FIG. 13.

Elevator

An elevator 41 having three decks 43, 44 and 46 is illustrated in FIG.2, which shows elevator 41 in its topmost position with its lower deck46 aligned with the infeed conveyor 63 and infeed staging platform 71.FIGS. 14C and 14G show the elevator 41 in its middle position with itsmiddle deck 43 in position for loading. FIG. 13 shows elevator 41 in itslowermost position with its upper deck 44 aligned with infeed conveyor63 and infeed staging platform 71 just prior to translation movement ofpusher 51 to deliver columns of containers 64 onto upper deck 44 ofelevator 41.

The vertical adjustment mounting of top deck 44 and bottom deck 46 isbest seen in FIGS. 9 and 13. There, angle brackets 47 having a verticalslotted flange are shown bolted through vertical slots into corner posts48 of elevator 41, supporting top deck 44, and bottom deck 46 issupported by similar angle brackets 47. A jack screw 49 mounted forvertical jacking movement relative to corner post 48 and bearing againsteach angle 47 allows the angles 47 to be raised or lowered as desired.These jack screws are also clearly shown in FIG. 13, and permit thevertical spacing between decks 43, 44 and 46 to be adjusted in order tomatch the vertical spacing between the shelves of the rolling cart 39,as indicated in FIG. 2.

Also shown in FIG. 13 are adjustable lower stops 78, comprising threadedbolts mounted for vertical adjustment in suitable threaded apertures ina stop bracket 79 extending laterally from the lower side bar 81,substantially in the middle of each lower side end of elevator 41, forengagement with the lower side rails 26, as elevator 41 reaches thelower end of its travel, as indicated in FIG. 13. Corner posts 48 ofelevator 41 are embraced by angles 82 welded to the main frame membersand defining the vertical elevator "shaft" within which elevator 41reciprocates vertically.

Shown in FIGS. 2 and 13 is a bridge beam 83 overlying the upper end ofthe elevator 41 and extending from front to rear, connected at itscenter point by an hoisting chain 84 which extends upward from elevator41 over a sprocket wheel 86 mounted to rotate in the central verticalplane of the frame 21. Sprocket wheel 86 is mounted for rotation on ahorizontal transverse shaft 87 journalled in bearing blocks 88 mountedon short longitudinal frame members positioned above the uppermost planeof the frame 21 defined by upper side rails 27 and top rails 24.

Offset from the central vertical plane of frame 21 toward the left sideof the frame is a second sprocket wheel 89 also keyed on shaft 87 andconnected to a second counterweight chain 91 secured to the periphery ofoffset sprocket wheel 89. Chain 91 extends from the uppermost peripheryof wheel 89 rearward toward a second smaller counterweight sprocketwheel 92 mounted on a rear shaft 93 which has its ends journalled in twoend bearing blocks. These are a bearing block 94 (FIG. 3) bolted to thetop side of the left upper side rail 27, and a cantilevered bearingblock 96 (FIGS. 4 and 7) extending rearward above the transverse framemember 33. This is a sturdy beam illustrated as a doublerectangular-section box beam 33 welded in position spanning the upperface of frame 21 between upper side rails 27 and between rearmostcentral side posts 31 and the rear corner posts 22.

The offset counterweight chain 91 extends rearward from the offsetsprocket 89 over counterweight sprocket wheel 92 from which it descendsto the counterweight supporting balance arm 97, as indicated in FIGS. 2,3, and 5-7. Chain 91 has its forward end secured to the periphery ofoffset sprocket wheel 89 at a point which allows shaft 87 to rotatethrough the entire arc required to provide full angular reciprocation ofbalance arm 97 from its lowermost position 97A shown in FIG. 2, to itsuppermost position 97B. The vertical center plane sprocket wheel 86 overwhich hoisting chain 84 is engaged has the free upper end of hoistingchain 84 secured to the periphery of wheel 86 at a point which allowsthe identical arc of rotation of shaft 87 to provide the lowering andraising of the length of hoisting chain 84 required to lower and raiseelevator 41 between its top position shown in FIG. 2 and its bottomposition shown in FIG. 13.

In the illustrated embodiment, this reciprocal stroke length of elevator41 is typically 23 inches, the distance which amounts to double thedistance between the container supporting surfaces of adjacent shelveson cart 39. Sprocket wheels 86 and 89, each being of one foot diameter,provide ample circumference to accommodate the length of hoisting chain84 and counterweight chain 91 required for this purpose.

Chain 91 and its sprocket wheels are laterally offset to permit theangular reciprocation of counterweight balance arm 97 in the rearcounterweight zone of frame 21 beside the elongated central pushercylinder 57, which is preferably centered to minimize dynamic twistingor skewing which might be accentuated if its piston rod were anchored tothe central pusher 51 at any point along its lateral dimension otherthan its central plane.

Clearly shown in FIGS. 1 and 13 are drawbridge or gangplank-style flipramps 98, having their rearmost edges hinged to the protruding forwardedges of each elevator deck 43, 44 and 46. These gangplank-style flipramps 98 are each actuated by small, diagonally pivoted air cylinders 99whose stationary ends are pivotally mounted on the elevator corner postabove each elevator deck, and whose articulating piston ends arepivotally mounted midway along the side edges of flip ramps 98, as shownin the drawings. The extension of these piston rods lowers the flipramps 98 to the cartloading position shown in FIG. 13, while retractionof the piston rods into cylinders 99 raises the flip ramps 98, assuringthat containers loaded on elevator 41 will not be inadvertentlydislodged during latching disengagement and removal of the filled cart39, and the latching engagement of the next empty cart for the nextcart-loading operation.

Counterweight Balance Arm

As clearly shown in FIGS. 5 and 7, the balance arm 97 has its forwardend sturdily pivoted for reciprocating angular motion to apivot-mounting block 101 which is securely anchored to the centraltransverse box beam 32, preferably formed as shown in FIG. 7 by a pairof square cross-section tubular box beams welded spanning the framebetween lower portions of middle side posts 29.

Mounted at the rear end of balance arm 97 is a counterweight 102 whoseweight is selected, when added to the weight of the associatedcomponents also supported by the counterweight chain 91, to approximatethe weight of elevator 41 when it is half loaded with containers 64,thus significantly minimizing the force required to raise and lowerelevator 41 between its limit positions.

A series arrayed pair of pneumatic cylinders 103 and 104 have theirfixed ends anchored together, with their central axes co-axially alignedalong a generally vertical axis extending from balance bar 97 tooverlying transverse top box beam 33, to which piston rod 106 of theupper cylinder 103 is pivotally anchored by a sturdy pivot block 107, asshown in FIGS. 2 and 4.

To avoid twisting of pneumatic hoses powering the cylinders 103 and 104,an anti-twist guide rod 105 depending from upper piston rod 106 extendsdownward over the length of cylinder 103 and parallel thereto, as shownin FIG. 7. A follower block 105A bolted to the upper end of cylinder 103is bored for telescoping sliding engagement with guide rod 105,resisting any tendency for connected cylinders 103-104 to rotate as theyextend and retract.

Piston rod 108 of lower cylinder 104 has its downwardly extending freeend pivotally mounted in a similar pivot block 109 and 107 slotted forsliding longitudinal movement along balance bar 97 to which the block109 is bolted through longitudinal slots in its base. Block 109 is alsoprovided with a longitudinal threaded aperture through which anadjustment lead screw 111 is threadedly engaged. Lead screw 111 is alsothreaded into a fixed block 112 bolted to balance arm 97, wherebyrotational adjustment of lead screw 111 causing its longitudinaltranslation relative to block 112 and balance bar 97 causes pivot block109 to move longitudinally along bar 97, after which its bolts may bytightened to secure block 109 in the desired adjusted position at aselected radius from the pivot pin joining bar 97 to block 101 ontransverse beam 32.

This adjustment of lead screw 111 producing the desired fine adjustmentin the reciprocating radius from pivot block 101 of the pivot pinjoining piston rod 108 to balance arm 97 selects the balance arm strokeangle between positions 97A and 97B shown in FIG. 2, and correspondinglyadjusts the total stroke length of elevator 41 to the desired dimension,which corresponds to twice the spacing between shelves of cart 39 in theillustrated embodiment.

The pivoted connection between the lower end of counterweight chain 91and balance arm 97 is likewise adjustable through a turnbuckleconnection 113 cooperating with a pivot block 114 secured to balance arm97. Adjustment of turnbuckle 113 allows the angular adjustment of thesprocket wheel shaft 87 above elevator 41 to raise or lower the elevatorto the precise limit positions desired, to match the height of shelvesof cart 39 latched in the loading zone 38. As indicated in the drawings,the two pneumatic cylinders 103 and 104 connected in seriesautomatically allow the elevator 41--balance arm 97 mechanism to attainits three predetermined positions in which the elevator decks arealigned with the shelves of cart 39, by dimensioning cylinders 103 and104 to bring balance bar 97 to its upper position 97B when both pistonsare retracted into both cylinders, lowering elevator 41 to its lowermostposition; by extending one piston, such as the lower piston 108 fromlower cylinder 104, to lower balance bar 97 to its central positionshown in FIGS. 2 and 7 while maintaining the upper piston 106 retracted,elevator 41 is brought to its middle position as illustrated in FIGS. 1,3 and 8; and by bringing balance bar 97 to its lower position 97A byextending both pistons 106 and 108, as shown in FIGS. 1, 3, 5, 6 and 13,elevator 41 is brought to its lowermost position.

Cart Loading Zone

In order to assure alignment of cart 39 with the decks of elevator 41for loading of containers 64 from the elevator directly to the shelvesof cart 39, the cart loaders of the present invention incorporatelatching mechanisms for guiding and securing cart 39 in its loadingposition in cart loading zone 38.

Positioned in the lower front corner of each front corner post 22 is aconverging guide flange 116, as shown in FIGS. 2A, 8, 11 and 12. As afresh, unloaded cart 39 is maneuvered into position in front of theframe 21, its corners engage the guide flanges 116 and guide it into aposition juxtaposed with the open front face of the elevator shaftportion of the cart loader 20.

Pivoting upper and lower latch blocks 117 and 119, mounted on a pivotrod 118 having a vertical axis journalled close to each front cornerpost 22 for pivotal movement relative thereto, provide the latchingengagement securing cart 39 in its loading position in the cart loadingzone 38. The upper right cart latch 117 is shown in FIG. 10, and theupper left cart latch 117 is shown in FIG. 11. The lower right cartlatch 119 at the lower end of pivot rod 118 is shown in FIG. 12.

A cart sensor 121 is mounted in the path of cart 39 to be pivotedrearwardly as the cart is maneuvered into position between guide flanges116 and latched behind the cart latch blocks 117 and 119. Sensors 121are best seen in FIGS. 10 and 11, and these sensors assure that loadingof containers from elevator 41 to cart 39 will be delayed until cart 39is latched in its loading position in the cart loading zone 38. Cart 39is customarily provided with a vertically sliding gate 122, similar tothe vertically sliding gates normally mounted on hospital beds to assurethat patients will not roll out of the bed. Cart gate 122 is shown inFIG. 2, and in the latched position of cart 39 secured by latchingblocks 117 and 119, the uppermost bar of gate 122 is positioned directlyabove a gate lift flange 45 of gate lift mechanism 42, shown in FIGS. 1and 2. The gate lift mechanism 42 is mounted vertically on the upperfront central portion of frame 21, and comprises a pneumatic cylinderwhose piston rod extends downward to provide support for gate liftflange 45. When the piston is retracted into this pneumatic cylinder,gate lift flange 45 is drawn upward, raising the cart gate 122 to itsloading position where its horizontal bars are aligned just below thecart shelves, providing lateral access for sliding delivery ofcontainers 64 from the decks of elevator 41 down gangplank flip ramps 98onto the shelves of cart 39.

It should be noted that pusher 51 with its extra long actuating cylinder57 is provided with three delivery positions, best shown in FIG. 13:position 51A is the first of these pusher positions, in which containers64 move from infeed conveyor 63 to infeed staging platform 71. Thesecond position 51B, just beyond staging platform 71, is the position atwhich pusher 51 has delivered the last column of containers 64 onto thethe deck of elevator 41 in FIG. 14F, thus providing four columns ofcontainers 64 on the elevator deck corresponding to the four columns ofcontainers illustrated on middle deck 43 and lower deck 46 in FIG. 13.The final position 51C of the pusher 51 is illustrated at the lefthandcentral portion of FIG. 13, corresponding to terminal positions 54C and56C for the two lower pushers 54 and 56, and corresponding to the frontedge of the middle and lower decks 43 and 46 of elevator 41. If flipramps 98 remain between the righthand row of containers 64 and the shelfof cart 39 on which the containers have been delivered by these pushersin their positions 51C, 54C and 56C, lowering of the cart gate byextension of the cylinder actuating the gate lift flange 45 will assurethat these containers remain on the cart shelves when the cart isunlatched and disengaged from the cart loader 20, and the flip ramps 98will slide out from between the containers 64 and cart shelves as thecart is rolled away from the cart loader. Thereafter, flip ramps 98 canbe hinged upwardly as their cylinders 99 are retracted in preparationfor the next loading operation.

While four columns of one-gallon milk containers are here described asfilling each elevator deck and each cart shelf, more columns of smallercontainers or fewer columns of larger containers may also be used ifdesire.

Operating Cycle

The successive schematic diagrams of FIGS. 14A through 14H illustratetypical successive steps in the operating cycle of the cart loaders ofthe present invention. In the preferred embodiment adapted to load afive-tiered cart 39, illustrated in the figures, the fully loaded cartis shown in FIG. 14A, where its top two shelves have just been loaded bythe advance of the upper pushers 52 and 53 urging the columns ofcontainers arrayed on the two upper decks of elevator 41 onto the twoupper cart shelves. At the same time, two new columns of containers arebeing assembled at the infeed conveyor and the infeed staging platform.

FIG. 14B shows the fully loaded cart 39 being withdrawn, and the firstof the same two columns of containers has now been delivered to the nearhalf of the elevator's lower deck while a third column of containers isadvancing down the infeed conveyor.

In FIG. 14C a new empty cart 39 has been rolled into position andlatched in place in front of the cart loader. The elevator 41 has nowhad its lower deck loaded with four columns of containers, and theelevator has been lowered one level to expose its middle deck forloading.

In FIG. 14D both lower decks of elevator 41 have been loaded and theelevator has been lowered to the bottom of its reciprocating stoke. Thefirst two columns of containers have just been loaded on the near halfof the elevator's upper deck by the central pusher 51.

In FIG. 14E three full elevator decks loaded with arrayed columns ofcontainers have just been swept from the elevator decks onto the latchedcart, which now has its three lower shelves filled with containers andthe central pusher 51 and the two lower pushers 54 and 56 are both shownat the completion of their advance stroke.

In FIG. 14F, while elevator 41 remains at the lower end of itsreciprocating stroke, four new columns of containers have been loaded onthe uppermost shelf of the elevator. In FIG. 14G, the elevator has beenraised one level, and its middle deck is shown half loaded with the nexttwo columns of containers ready for delivery to its middle deck from theinfeed conveyor and the infeed staging platform.

In FIG. 14H, the elevator with its middle and upper decks fully loadedhas been raised to its upper position, with its empty lower deck alignedwith the infeed conveyor. As the first row of containers advances downthe infeed conveyor in front of central pusher 51, the two upper pushers52 and 53 are both actuated to advance all containers from both upperdecks of the elevator to the two top shelves of cart 39, producing thefully loaded cart shown in FIG. 14A, and the operating cycle isrepeated.

Rolling carts with even numbers of two, four, or six shelves may be usedif desired, but multi-tiered carts with odd numbers of shelves arebelieved to be more time-effective. When a cart with an odd number ofthree, five, seven, or nine shelves is employed, this number of shelvesmay be represented by the expression 2N+1, and it is believed that anelevator with N+1 decks is most efficient in achieving minimum cycletime accompanied by maximum cart switching time for removal of thefilled cart shown in FIG. 14A and FIG. 14B, and the maneuvering andlatching of an empty cart into position ready for loading, shown inFIGS. 14C and 14D.

Thus a seven-shelf cart would employ a four-shelf elevator; thefive-shelf cart, illustrated in the drawings, employs a three-shelfelevator; and a three-shelf cart would employ a two-shelf elevator. Thesize and weight of the objects being loaded from the infeed conveyoronto the multi-tiered cart will of course govern the convenient size andmaneuverability of the loaded cart, dictating the number of shelvesselected for maximum convenience of the users.

While the operating cycle has been illustrated with the lower threeshelves of the five-tiered cart 39, being loaded first in FIG. 14E, andthe top two shelves being loaded at the end of the operating cycle inFIGS. 14H and 14A, with the lower deck of the elevator being reloadedduring cart switching and unlatching, as shown in FIG. 14B. However,either end of the elevator stroke may be employed for this purpose solong as the remaining elevator deck is aligned for reloading during thecart unlatching and switching steps. If all N+1 elevator decks areloaded simultaneously onto either the topmost or lowermost N+1 cartshelves, the remaining N cart shelves can be loaded simultaneously whilethe last elevator deck is being loaded. Thus the top three shelves ofthe five-tier cart may be loaded first, if desired, with the elevatorthen proceeding downward and being loaded successively until all of itslower two decks are fully loaded, after which those lower two decks maybe transferred to the lower two shelves of the cart, while the upperdeck of the elevator is being reloaded. The filled cart can be unlatchedand removed as the elevator is being loaded and raised to successivelevels, performing the reverse loading operation as compared to thatillustrated in FIGS. 14A through 14H but achieving the same advantagesand minimum cycle time.

When a cart 39 with an even number of 2N shelves is filled from anelevator 41, optimum use of elevator cargo space is believed to resultwhen the elevator has 1/2 of 2N or N shelves, leaving a maximum of 50%of the operating cycle for changing carts before the elevator is fullyloaded. When a cart 39 with an odd number of 2N+1 a shelves is employed,the most efficient use of elevator cargo space is believed to beachieved by an elevator of N+1 shelves, leaving more than 50% of theoperating cycle for changing carts: 4/7 or 57% when N=3, and 3/5 or 60%when N=2 as in the illustrated embodiment.

The electrical or pneumatic cycle control systems and the sensors,timers, counters and limit switches triggering each successive step inthe operating cycle are believed to utilize well-known principles andsystems, and therefore circuit diagrams and detailed control sequenceshave been omitted in order to emphasize the cooperating features andadvantages of the present invention which are believed to be unique.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope on the invention which, as amatter of language, might be said to fall therebetween.

In the claims:

We claim:
 1. A cart loader for assembling objects advancing along aninfeed conveyor line into at least one column of objects, andtransferring these objects to individual shelves of a multi-tieredrolling cart, comprising:A. a frame enclosing(1) a vertically elongatedfront elevator zone, and (2) a central staging zone rearwardly behindthe elevator zone aligned to receive objects delivered by the infeedconveyor, as at least one lateral column across the staging zone, B. amulti-deck elevator movably mounted for reciprocating vertical movementwithin the elevator zone and having at least two decks spaced apartvertically by a distance corresponding to the vertical distance betweenshelves on the multi-tiered cart, C. cart latching means mounted on thefront of the frame and defining the rear portion of a cart loading zonein which the multi-tiered cart is disengageably latched to the framewith its individual shelves presented to the elevator zone for loading,D. a plurality of horizontally forward deployable and rearwardretractable pushers corresponding to the number of shelves of themulti-tiered cart, each pusher being aligned with one said shelf whenthe cart is latched to the frame, and positioned for delivery of objectsfrom the elevator zone to the cart-loading zone, with one verticallycentral pusher being aligned with the infeed conveyor and having atleast two forward stop positions, a proximal stop position in whichobjects propelled by the central pusher are delivered from the infeedconveyor to the aligned elevator deck and a remote stop position inwhich objects propelled by the central pusher have been swept from theelevator deck and delivered forward to the aligned cart shelf, E.elevator hoisting-lowering means connected to move the elevator betweena top position with its uppermost deck substantially aligned with thetop shelf of the cart, and a bottom position with its lowermost decksubstantially aligned with the bottom shelf of the cart, F. and elevatorstop means connected to stop the elevator at successive levels with eachof its decks in turn aligned with the infeed conveyor and with one ofsaid pushers.
 2. The cart loader defined in claim 1 wherein the elevatoris provided with at least half as many decks as the number of shelves inthe multi-tiered cart.
 3. The cart loader defined in claim 1 wherein theelevator is provided with N+1 decks and the multi-tiered cart isprovided with 2N+1 shelves, where N is an integer greater than zero. 4.The cart loader defined in claim 1 wherein each non-central pusher aboveand each non-central pusher below said central pusher has a retractedrear position clear of the elevator zone, and an extended remote forwardstop position in which an object propelled by said non-central pusherhas been swept forward from an aligned elevator deck and delivered tothe aligned cart shelf.
 5. The cart loader apparatus defined by claim 4,wherein all pushers above the central pusher are actuatedsimultaneously, and all pushers below the central pusher are actuatedsimultaneously.
 6. The cart loader apparatus defined in claim 3 whereinN=2.
 7. The cart loader defined in claim 1 including a counterweightmounted at one end of a balance bar whose other end is pivotallyconnected to said frame, and wherein said hoisting-lowering means andsaid elevator stop means include a sprocket wheel chain assemblyconnecting the elevator to the balance beam, and an extensible andretractable pneumatic piston-cylinder assembly suspending the balancebar from the frame in a rear counterweight zone and having a pluralityof stop positions corresponding to the number of said elevator decks. 8.The cart loader defined in claim 7, further including an adjustableturnbuckle interposed in the sprocket wheel chain assembly, whereby fineadjustment of the successive elevator levels is achieved.
 9. The cartloader defined in claim 7, further including a movable connector joiningthe piston-cylinder assembly to the balance bar whereby the distancebetween said elevator levels is adjusted.
 10. The cart loader defined inclaim 7, wherein the counterweight and balance bar are selected tosubstantially match the weight of the elevator in its half-loadedcondition.
 11. The cart loader defined in claim 7, wherein thepiston-cylinder assembly is a substantially vertically and co-axiallyaligned pair of pneumatic cylinders having their blind ends anchoredtogether, with their respective pistons oppositely extending forrespective pivoting connections with said frame and said balance bar.12. The cart loader defined in claim 1 wherein the infeed conveyorextends laterally across the width of the frame directly behind thestaging zone, further including an upwardly extendible guide barpositioned beside the forward edge of the infeed conveyor to alignobjects traveling thereon, which is downwardly retractable duringactuation of the central pusher associated with the infeed conveyor. 13.The cart loader defined in claim 1, further including a staging platformpositioned beside the infeed conveyor to receive a column of objectsdelivered one object's width by actuation of the pusher associated withthe infeed conveyor.
 14. The cart loader defined in claim 1 wherein theelevator is provided with a gangplank-style flip ramp hinged to thefront edge of each elevator deck, retracted upward to retain objects onthe elevator deck and deployed forward to release objects for loadingfrom the elevator deck to the aligned cart shelf.
 15. The cart loaderdefined in claim 1 wherein the cart latching means comprise latch blockspivotable into latching engagement with the cart.
 16. The cart loaderdefined in claim 15, further including converging guide flanges mountedon the frame and positioned to direct each arriving cart into seatedengagement, anchored by the latch blocks.
 17. A method for loading at aloading station a multi-tiered cart having 2N+1 shelves with objectsdelivered on an infeed conveyor positioned at the level of the middlecart tier, utilizing an elevator positioned between the infeed conveyorand the cart and having N+1 decks, wherein N is an integer greater thanzero, comprising the steps ofA. moving the elevator to a first end ofits stroke, with a proximal elevator deck aligned with the infeedconveyor and the level of the middle cart tier, and a distal elevatordeck aligned with a last cart tier, B. pushing objects from the infeedconveyor to the proximal elevator deck until said deck is filled, C.moving the elevator toward the opposite end of its stroke to align itsnext deck with the infeed conveyor, D. pushing objects from the infeedconveyor to said next elevator deck until said next deck is filled, E.repeating steps C and D until the elevator has reached said opposite endof its stroke and all elevator decks are filled, F. simultaneouslypushing all objects loaded on all elevator decks onto aligned carttiers, G. pushing objects from the infeed conveyor to load the distalelevator deck, H. moving the elevator toward said first end of itsstroke until the next elevator deck is aligned with the infeed conveyor,I. pushing objects from the infeed conveyor to said next elevator deckuntil said next deck is filled, J. repeating steps H and I until saidelevator is at said first end of its stroke and all elevator decksexcept said proximal deck are filled, K. simultaneously pushing allobjects from all said elevator decks except said proximal deck ontoaligned cart tiers, thereby completing the loading of all tiers of saidcart, L. repeating steps B, C and D while removing the loaded cart andsubstituting an empty cart into loading position at the loading station,M. repeating steps E, F, G, H, I, J and K, whereby a continuous seriesof empty carts are loaded in turn.